Recently, there is extensively used an endoscope (called also a scope or fiber scope) whereby, by inserting an elongate insertable part through a body cavity, organs within the body cavity can be observed or, as required, by using a treating tool inserted through a treating tool channel, various curving treatments can be made.
Also, there are suggested various electronic scopes wherein a solid state imaging device such as a charge coupled device (CCD) is used. There are advantages that such an electronic scope is higher in the resolution and easier to record and reproduce picture images than the fiber scope and it is easier in such a picture image process to magnify of the picture image and to compare two picture images.
As systems of imaging color picture images of the above mentioned electronic scope, there are a frame sequential type sequentially switching the illuminating light to R (red), G (green) and B (blue) as shown, for example, in the gazette of a Japanese patent laid open No. 82731/1986 and a color mosaic type (called also a synchronous type) in which a filter array in which color filters respectively transmitting color lights of R, G and B are arranged in a mosaic form is provided on the front surface of a solid state imaging device. The frame sequential type has an advantage because the number of pixels can be made smaller than in the color mosaic type. On the other hand, the color mosaic type has an advantage because no color is displaced.
The above mentioned electronic scope can be varied depending upon the objects on which it is used. For example, for the upper or lower digestive organ, an insertable part of an outside diameter of about 10 mm is used. On the other hand, for the bronchus, usually an outside diameter less than about 5 mm is required. It is unreasonable physically and functionally to use the same kind of imaging device and the same kind of imaging system for various electronic scopes of outside diameters of the insertable parts in such a wide range. That is to say, in order to realize an electronic scope, for example, for the bronchus (fine diameter), an imaging device of a small number of pixels must be used.
In case the number of pixels is small, in order to prevent the reduction of the resolution, the frame sequential type color imaging system, wherein an object is illuminated in a frame sequential system with the lights of the respective wavelengths of R, G and B and is frame sequentially imaged under the illumination and the images are composed and color-displayed, is more advantageous than the color-mosaic type imaging system using color mosaic filters.
On the other hand, it is advantageous for the improvement of the picture quality to make the imaging system a color mosaic type by making the number of pixels large for the outside diameter of about 10 mm.
Now, the above mentioned fiber scope or electronic scope is used as connected to a light source apparatus generally feeding illuminating lights adapted to the respective scopes.
The illuminating method is different in the above mentioned fiber scope, frame sequential type electronic scope and color mosaic type electronic scope. That is to say, the fiber scope and color mosaic type electronic scope require a white light and the frame sequential type electronic scope requires a light sequentially switchable to R, G and B. However, the conventional light source apparatus can output only an illuminating light corresponding to either of the frame sequential type electronic scope and color mosaic type electronic or fiber scope. Therefore, the user is required to prepare respectively different light source apparatus depending on the kind of the scope and the economy and efficiency were low. In the gazette of a Japanese patent laid open No. 243625/1985, there is disclosed a connecting system whereby a fiber scope provided with an image transmitting optical fiber bundle is connected to a control apparatus of an electronic scope provided with a frame sequential type light source apparatus so that the object image may be observed on the displaying picture surface of a monitor television or the like. However, in this system, the color mosaic type electronic scope can not be used and the image cannot be observed with a naked eye by using the fiber scope.